From 06032b209ee750aa0d51248525362d61b5d1df23 Mon Sep 17 00:00:00 2001 From: ictlyh Date: Wed, 5 Apr 2017 19:26:21 +0800 Subject: [PATCH] Translated tech/20170321 How to Install a DHCP Server in CentOS RHEL and Fedora.md --- ...a DHCP Server in CentOS RHEL and Fedora.md | 207 ------------------ ...a DHCP Server in CentOS RHEL and Fedora.md | 203 +++++++++++++++++ 2 files changed, 203 insertions(+), 207 deletions(-) delete mode 100644 sources/tech/20170321 How to Install a DHCP Server in CentOS RHEL and Fedora.md create mode 100644 translated/tech/20170321 How to Install a DHCP Server in CentOS RHEL and Fedora.md diff --git a/sources/tech/20170321 How to Install a DHCP Server in CentOS RHEL and Fedora.md b/sources/tech/20170321 How to Install a DHCP Server in CentOS RHEL and Fedora.md deleted file mode 100644 index ffdb08a7e8..0000000000 --- a/sources/tech/20170321 How to Install a DHCP Server in CentOS RHEL and Fedora.md +++ /dev/null @@ -1,207 +0,0 @@ -ictlyh translating - -How to Install a DHCP Server in CentOS, RHEL and Fedora -============================================================ - - -DHCP (Dynamic Host Configuration Protocol) is a network protocol that enables a server to automatically assign an IP address and provide other related network configuration parameters to a client on a network, from a pre-defined IP pool. - -This means that each time a client (connected to the network) boots up, it gets a “dynamic” IP address, as opposed to “static” IP address that never changes. The IP address assigned by a DHCP server to DHCP client is on a “lease”, the lease time can vary depending on how long a client is likely to require the connection or DHCP configuration. - -In this tutorial, we will cover how to install and configure a DHCP server in CentOS/RHEL and Fedora distributions. - -#### Testing Environment Setup - -We are going to use following testing environment for this setup. - -``` -DHCP Server - CentOS 7 -DHCP Clients - Fedora 25 and Ubuntu 16.04 -``` - -#### How Does DHCP Work? - -Before we move any further, let’s briefly explain how DHCP works: - -* When a client computer (configured to use DHCP) and connected to a network is powered on, it forwards a DHCPDISCOVER message to the DHCP server. -* And after the DHCP server receives the DHCPDISCOVER request message, it replies with a DHCPOFFER message. -* Then the client receives the DHCPOFFER message, and it sends a DHCPREQUEST message to the server indicating, it is prepared to get the network configuration offered in the DHCPOFFERmessage. -* Last but not least, the DHCP server receives the DHCPREQUEST message from the client, and sends the DHCPACK message showing that the client is now permitted to use the IP address assigned to it. - -### Step 1: Installing DHCP Server in CentOS - -1. Installing DCHP is quite straight forward, simply run the command below. - -``` -# yum -y install dhcp -``` - -Important: Assuming there is more than one network interface attached to the system, but you want the DHCP server to only be started on one of the interfaces, set the DHCP server to start only on that interface as follows. - -2. Open the file /etc/sysconfig/dhcpd, add the name of the specific interface to the list of DHCPDARGS, for example if the interface is `eth0`, then add: - -``` -DHCPDARGS=eth0 -``` - -Save the file and exit. - -### Step 2: Configuring DHCP Server in CentOS - -3. For starters, to setup a DHCP server, the first step is to create the `dhcpd.conf` configuration file, and the main DHCP configuration file is normally /etc/dhcp/dhcpd.conf (which is empty by default), it keeps all network information sent to clients. - -However, there is a sample configuration file /usr/share/doc/dhcp*/dhcpd.conf.sample, which is a good starting point for configuring a DHCP server. - -And, there are two types of statements defined in the DHCP configuration file, these are: - -* parameters – state how to carry out a task, whether to perform a task, or what network configuration options to send to the DHCP client. -* declarations – specify the network topology, define the clients, offer addresses for the clients, or apply a group of parameters to a group of declarations. - -Therefore, start by copying the sample configuration file as the main configuration file like so: - -``` -# cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf -``` - -4. Now, open the main configuration file and define your DHCP server options: - -``` -# vi /etc/dhcp/dhcpd.conf -``` - -Start by setting the following global parameters which will apply to all the subnetworks (do specify values that apply to your scenario) at the top of the file: - -``` -option domain-name "tecmint.lan"; -option domain-name-servers ns1.tecmint.lan, ns2.tecmint.lan; -default-lease-time 3600; -max-lease-time 7200; -authoritative; -``` - -5. Now, define a subnetwork; in this example, we will configure DHCP for 192.168.56.0/24 LAN network (remember to use parameters that apply to your scenario): - -``` -subnet 192.168.56.0 netmask 255.255.255.0 { -option routers 192.168.56.1; -option subnet-mask 255.255.255.0; -option domain-search "tecmint.lan"; -option domain-name-servers 192.168.56.1; -range 192.168.56.10 192.168.56.100; -range 192.168.56.120 192.168.56.200; -} -``` - -### Step 3: Assign Static IP to DHCP Client - -You can assign a static IP address to a specific client computer on the network, simply define the section below in /etc/dhcp/dhcpd.conf file, where you must explicitly specify it’s MAC addresses and the fixed IP to be assigned: - -``` -host ubuntu-node { -hardware ethernet 00:f0:m4:6y:89:0g; -fixed-address 192.168.56.105; -} -host fedora-node { -hardware ethernet 00:4g:8h:13:8h:3a; -fixed-address 192.168.56.110; -} -``` - -Save the file and close it. - -Note: You can find out or display the Linux MAC address using following command. - -``` -# ifconfig -a eth0 | grep HWaddr -``` - -6. Now start the DHCP service for the mean time and enable it to start automatically from the next system boot, using following commands: - -``` ----------- On CentOS/RHEL 7 ---------- -# systemctl start dhcpd -# systemctl enable dhcpd ----------- On CentOS/RHEL 6 ---------- -# service dhcpd start -# chkconfig dhcpd on -``` - -7. Next, do not forget to permit DHCP service (DHCPD daemon listens on port 67/UDP) as below: - -``` ----------- On CentOS/RHEL 7 ---------- -# firewall-cmd --add-service=dhcp --permanent -# firewall-cmd --reload ----------- On CentOS/RHEL 6 ---------- -# iptables -A INPUT -p tcp -m state --state NEW --dport 67 -j ACCEPT -# service iptables save -``` - -### Step 4: Configuring DHCP Clients - -8. Now, you can configure your clients on the network to automatically receive IP addresses from the DHCP server. Login to the client machine and modify the Ethernet interface configuration file as follows (take not of the interface name/number): - -``` -# vi /etc/sysconfig/network-scripts/ifcfg-eth0 -``` - -Add the options below: - -``` -DEVICE=eth0 -BOOTPROTO=dhcp -TYPE=Ethernet -ONBOOT=yes -``` - -Save the file and exit. - -9. You can also perform the settings using the GUI on a desktop computer, set the Method to Automatic (DHCP) as shown in the screenshot below (Ubuntu 16.04 desktop). - -[ - ![Set DHCP in Client Network](http://www.tecmint.com/wp-content/uploads/2017/03/Set-DHCP-in-Client-Network.png) -][3] - -Set DHCP in Client Network - -10. Then restart network services as follows (you can possibly reboot the system): - -``` ----------- On CentOS/RHEL 7 ---------- -# systemctl restart network ----------- On CentOS/RHEL 6 ---------- -# service network restart -``` - -At this point, if all settings were correct, your clients should be receiving IP addresses automatically from the DHCP server. - -You may also read: - -1. [How to Install and Configure Multihomed ISC DHCP Server on Debian Linux][1] -2. [10 Useful “IP” Commands to Configure Network Interfaces][2] - -In this tutorial, we showed you how to setup a DHCP server in RHEL/CentOS. Use the comment form below to write back top us. In an upcoming article, we will show you how to setup a DHCP server in Debian/Ubuntu. Until then, always stay connected to TecMint. - --------------------------------------------------------------------------------- - -作者简介： - -Aaron Kili is a Linux and F.O.S.S enthusiast, an upcoming Linux SysAdmin, web developer, and currently a content creator for TecMint who loves working with computers and strongly believes in sharing knowledge. - --------------------------------------------------------------------------------- - -via: http://www.tecmint.com/install-dhcp-server-in-centos-rhel-fedora/ - -作者：[Aaron Kili][a] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]:http://www.tecmint.com/author/aaronkili/ -[1]:http://www.tecmint.com/install-and-configure-multihomed-isc-dhcp-server-on-debian-linux/ -[2]:http://www.tecmint.com/ip-command-examples/ -[3]:http://www.tecmint.com/wp-content/uploads/2017/03/Set-DHCP-in-Client-Network.png -[4]:http://www.tecmint.com/author/aaronkili/ -[5]:http://www.tecmint.com/10-useful-free-linux-ebooks-for-newbies-and-administrators/ -[6]:http://www.tecmint.com/free-linux-shell-scripting-books/ diff --git a/translated/tech/20170321 How to Install a DHCP Server in CentOS RHEL and Fedora.md b/translated/tech/20170321 How to Install a DHCP Server in CentOS RHEL and Fedora.md new file mode 100644 index 0000000000..33fa8c3bc3 --- /dev/null +++ b/translated/tech/20170321 How to Install a DHCP Server in CentOS RHEL and Fedora.md @@ -0,0 +1,203 @@ +如何在 CentOS、RHEL 和 Fedora 上安装 DHCP 服务 +============================================================ + +DHCP（Dynamic Host Configuration Protocol）是一个网络协议，它使得服务器能从预定义的 IP 池中为网络中的客户端节点自动分配 IP 地址并提供其它相关的网络配置参数。 + +这意味着每次客户端节点启动（连接到网络）的时候，它都会获得一个和从不改变的“静态” IP 地址相反的“动态” IP 地址。DHCP 服务器给 DHCP 客户端分配 IP 地址称为“租约”，租约时间随客户端需要的连接时间或 DHCP 的配置而异。 + +在这篇指南中，我们会介绍如何在 CentOS/RHEL 和 Fedora 发行版中安装和配置 DHCP 服务。 + +#### 设置测试环境 + +本次安装中我们使用如下的测试环境。 + +``` +DHCP 服务器 - CentOS 7 +DHCP 客户端 - Fedora 25 和 Ubuntu 16.04 +``` + +#### DHCP 如何工作？ + +在进入下一步之前，让我们首先了解一下 DHCP 的工作流程： + +* 当已连接到网络的客户端计算机（配置为使用 DHCP）启动时，它会发送一个 DHCPDISCOVER 消息到 DHCP 服务器。 +* 当 DHCP 服务器接收到 DHCPDISCOVER 请求消息时，它会回复一个 DHCPOFFER 消息。 +* 客户端收到 DHCPOFFER 消息后，它再发送给服务器一个 DHCPREQUEST 消息，表示客户端已准备好获取 DHCPOFFER 消息中提供的网络配置。 +* 最后，DHCP 服务器收到客户端的 DHCPREQUEST 消息，并回复 DHCPACK 消息，表示允许客户端使用分配给它的 IP 地址。 + +### 第一步：在 CentOS 上安装 DHCP 服务 + +1. 安装 DHCP 服务非常简单，只需要运行下面的命令即可。 + +``` +$ yum -y install dhcp +``` + +重要：假如系统中有多个网卡，但你想只在其中一个网卡上启用 DHCP 服务，可以按照下面的步骤在该网卡上启用 DHCP 服务。 + +2. 打开文件 /etc/sysconfig/dhcpd，将指定网卡的名称添加到 DHCPDARGS 列表，假如网卡名称为 `eth0`，则添加： + +``` +DHCPDARGS=eth0 +``` + +保存文件并退出 。 + +### 第二步：在 CentOS 上配置 DHCP 服务 + +3. 对于初学者来说，配置 DHCP 服务的第一步是创建 `dhcpd.conf` 配置文件，DHCP 主要配置文件一般是 /etc/dhcp/dhcpd.conf（默认情况下该文件为空），该文件保存了发送给客户端的所有网络信息。 + +但是，有一个样例配置文件 /usr/share/doc/dhcp*/dhcpd.conf.sample，这是配置 DHCP 服务的良好开始。 + +DHCP 配置文件中定义了两种类型的语句： + +* 参数 - 说明如何执行任务、是否执行任务、或者给 DHCP 客户端发送什么网络配置选项。 +* 声明 - 指定网络拓扑、定义客户端、提供客户端地址、或将一组参数应用于一组声明。 + +因此，首先复制示例配置文件为主配置文件： + +``` +$ cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf +``` + +4. 然后，打开主配置文件并定义你的 DHCP 服务选项： + +``` +$ vi /etc/dhcp/dhcpd.conf +``` + +首先在文件开头设置以下应用于全部子网的全局参数（注意要使用你实际场景中的值）： + +``` +option domain-name "tecmint.lan"; +option domain-name-servers ns1.tecmint.lan, ns2.tecmint.lan; +default-lease-time 3600; +max-lease-time 7200; +authoritative; +``` + +5. 然后，定义一个子网；在这个事例中，我们会为 192.168.56.0/24 局域网配置 DHCP（注意使用你实际场景中的值）： + +``` +subnet 192.168.56.0 netmask 255.255.255.0 { +option routers 192.168.56.1; +option subnet-mask 255.255.255.0; +option domain-search "tecmint.lan"; +option domain-name-servers 192.168.56.1; +range 192.168.56.10 192.168.56.100; +range 192.168.56.120 192.168.56.200; +} +``` + +### 第三步：为 DHCP 客户端分配静态 IP + +只需要在 /etc/dhcp/dhcpd.conf 文件中定义下面的部分，其中你必须显式指定它的 MAC 地址和打算分配的 IP，你就可以为网络中指定的客户端计算机分配一个静态 IP 地址： + +``` +host ubuntu-node { +hardware ethernet 00:f0:m4:6y:89:0g; +fixed-address 192.168.56.105; +} +host fedora-node { +hardware ethernet 00:4g:8h:13:8h:3a; +fixed-address 192.168.56.110; +} +``` + +保存文件并关闭。 + +注意：你可以使用下面的命令找到 Linux 的 MAC 地址。 + +``` +$ ifconfig -a eth0 | grep HWaddr +``` + +6. 现在，使用下面的命令启动 DHCP 服务，并使在下次系统启动时自动启动： + +``` +---------- On CentOS/RHEL 7 ---------- +$ systemctl start dhcpd +$ systemctl enable dhcpd +---------- On CentOS/RHEL 6 ---------- +$ service dhcpd start +$ chkconfig dhcpd on``` + +7. 另外，别忘了使用下面的命令允许 DHCP 服务通过防火墙（DHCPD 守护进程通过 UDP 监听67号端口）： + +``` +---------- On CentOS/RHEL 7 ---------- +$ firewall-cmd --add-service=dhcp --permanent +$ firewall-cmd --reload +---------- On CentOS/RHEL 6 ---------- +$ iptables -A INPUT -p tcp -m state --state NEW --dport 67 -j ACCEPT +$ service iptables save +``` + +### 第四步：配置 DHCP 客户端 + +8. 现在，你可以为网络中的客户端配置自动从 DHCP 服务器中获取 IP 地址。登录到客户端机器并按照下面的方式修改以太网接口的配置文件（注意网卡的名称和编号）： + +``` +# vi /etc/sysconfig/network-scripts/ifcfg-eth0 +``` + +添加下面的选项： + +``` +DEVICE=eth0 +BOOTPROTO=dhcp +TYPE=Ethernet +ONBOOT=yes +``` + +保存文件并退出。 + +9. 你也可以在桌面服务器中按照下面的截图（Ubuntu 16.04桌面版）通过 GUI 设置 Method 为 Automatic (DHCP)。 + +[ + ![Set DHCP in Client Network](http://www.tecmint.com/wp-content/uploads/2017/03/Set-DHCP-in-Client-Network.png) +][3] + +在客户端网络中设置 DHCP + +10. 按照下面的命令重启网络服务（你也可以通过重启系统）： + +``` +---------- On CentOS/RHEL 7 ---------- +$ systemctl restart network +---------- On CentOS/RHEL 6 ---------- +$ service network restart +``` + +到了这里，如果所有设置都是正确的，你的客户端就应该能自动从 DHCP 服务器中获取 IP 地址。 + +你也可以阅读： + +1. [如何在 Debian Linux 中安装和配置 Multihomed ISC DHCP 服务][1] +2. [配置网络的10个有用的 “IP” 命令][2] + +在这篇文章中我们为你展示了如何在 RHEL/CentOS 中安装 DHCP 服务。在下面的评论框中给我们反馈吧。在接下来的文章中，我们还会为你展示如何在 Debian/Ubuntu 中安装 DHCP 服务。和 TecMint 保持联系。 + +-------------------------------------------------------------------------------- + +作者简介： + +Aaron Kili 是一个 Linux 和 F.O.S.S 的爱好者，即将推出的 Linux SysAdmin 网络开发人员，目前也是 TecMint 的内容创作者，他喜欢和电脑一起工作，并且坚信共享知识。 + +-------------------------------------------------------------------------------- + +via: http://www.tecmint.com/install-dhcp-server-in-centos-rhel-fedora/ + +作者：[Aaron Kili][a] +译者：[ictlyh](https://github.com/ictlyh) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:http://www.tecmint.com/author/aaronkili/ +[1]:http://www.tecmint.com/install-and-configure-multihomed-isc-dhcp-server-on-debian-linux/ +[2]:http://www.tecmint.com/ip-command-examples/ +[3]:http://www.tecmint.com/wp-content/uploads/2017/03/Set-DHCP-in-Client-Network.png +[4]:http://www.tecmint.com/author/aaronkili/ +[5]:http://www.tecmint.com/10-useful-free-linux-ebooks-for-newbies-and-administrators/ +[6]:http://www.tecmint.com/free-linux-shell-scripting-books/